Questions raised
When configuring the clock tree, I want to set the main frequency to 400Mhz, click Quick Settings, press Enter, and Frequency searched for is out of range for this VOS range appears.
However, this problem does not appear in CubeMx 6.1.1, and the newly installed 6.4.0 reports an error
problem finding
Since it is said that VOS reports an error, then let's take a look at VOS.
In the "STM32H7 Reference Manual", we can see that VOS is a voltage level setting. The level is different, and the highest frequency of the system clock operation is different. After the system is reset, select VOS3
– VOS1: Voltage regulation 1
– VOS2: Voltage regulation 2
– VOS3: Voltage regulation 3
After reset, the system starts with the lowest run mode voltage regulation (VOS3). After that, the VOS bit in the PWR D3 domain control register (PWR_D3CR) can be programmed by software according to the required system
performance. The smaller the level value, the higher the operating frequency, so if we want to configure the main frequency of H7 to be 400MHz, then we must configure The regulator output voltage level VOS is level 1 or 0
In the STM32F4 Chinese manual, the impact of VOS on the system clock frequency is clearly mentioned
problem solved
In the new version of CubeMx, the default is VOS3, and the system frequency cannot reach 400Mhz, so an error will be reported
So after setting the RCC, you also need to set the VOS level to 0 or 1
As for the following FLASH_LATENCY, H7 also gives a specific block diagram. At the VOS1 level, set 2 WS to ensure that the system FLASH code runs at the fastest frequency
For more details, see:
STM32H7 clock tree RCC analysis - principle explanation (1)
